President Donald Trump has claimed that pardons signed by his predecessor Joe Biden are invalid. His reasoning: They were allegedly signed with an autopen, a signing machine used by the U.S government for decades.

Donald Trump says Joe Biden's last-minutes pardons via autopen are null and void. But what is an autopen? And what does it mean for pardons?

O n Monday, President Donald Trump signaled that he intends to nullify the presidential pardons—issued to those on the House Jan. 6 committee that investigated Trump—executed by President Joe Biden because, he said, they were signed via autopen.